Broad search for trajectories from Earth to Callisto-Ganymede-JOI double-satellite-aided capture at Jupiter from 2020 to 2060.

Employing multiple gravity-assist flybys of Jupiter's Galilean moons can save a substantial amount of $$\varDelta V$$ when capturing into orbit about Jupiter. Using Callisto and Ganymede, the most massive and distant of the Galilean moons, as gravity-assist bodies reduces the Jupiter orbit insertion $$\varDelta V$$ cost, while allowing the spacecraft to remain above the worst of Jupiter's radiation belts. A phase-angle approach is used to find initial guesses for a Lambert targeter to find patched-conic Callisto-Ganymede transfers. A B-plane targeter using grid search methodology is used to backward target Earth to find launch conditions. Twenty-nine distinct patched-conic trajectories were found from Earth to Callisto-Ganymede-JOI capture throughout the search space from 2020-2060. Five promising trajectories were found that launch from Earth between July 11, 2023 and July 20, 2023, and arrive at Jupiter between February and September 2026. These trajectories were numerically integrated using GMAT and, in the author's opinion, are excellent candidates for use on NASA's planned Europa Clipper mission. [ABSTRACT FROM AUTHOR]